Incorporating Manufacturing Considerations

Integrating Manufacturing The traditional separation of functions in U.S. companies kept product designers far apart from manufacturing and process engineers. With the emphasis on developing better-performing products, containing more and more special features, the design engineers represented the elite group in advanced technology companies. Manufacturing and process engineers were relegated to secondary (and tertiary) roles; their job was to somehow figure out how to produce the products with sophisticated design features that were thrust upon them late in the planning cycle. It was not surprising that the initial production runs of products contained a high fraction of defective items and that production problems could never be completely eliminated. The problems of poor production processes for new products frequently became rationalized by referring to them as "learning problems." Companies built learning or experience curve effects into their cost-planning estimates. They failed, however, to investigate how much "learn-ing" occurred merely because they started from such an ignorant or inefficient base during initial production. Today, companies striving for zero defect production recognize that manufacturing considerations must be made part of any new-product design. All newproduct design teams include people with extensive production and procurement experience. Quality experts assert that only 20% of quality defects can be traced to the production line. The other 80% become locked in during the design stage or by purchasing based on low price rather than on the quality of parts and materials? Additional steps include extensive training of all personnel-workers and management—in how to achieve zero defect goals. The responsibility for detecting nonconforming items has been shifted from quality control inspectors to the persons actually performing the work. Operators now maintain their equipment, operate the machines well within acceptable and rated limits, and are expected to produce zero defect output. In some advanced manufacturing installations, the machines themselves perform quality checks, using computerized gauging devices, as the items are pro-duced. Extensive use of statistical process control (SPC) is employed throughout the factory floor to ensure that all production processes continually operate in control. Other techniques are often employed to reduce the incidence of defective production. The Taguchi method attempts to design equipment methods and products that are "robust against noise," such as product deterioration, manufacturing imperfections, and environmental factors. The adverse effects from such noise are reduced instead of attempting to eliminate the noise. This permits products to perform more consistently in service under a variety of conditions. Quality requirements were also imposed on suppliers. Companies have gone through several phases in their relationships with suppliers; shifting from the old policy of acceptance sampling of incoming items, to 100% inspection (with the entire batch returned if any defects were de-tected), to the current policy of performing no inspection at all of incoming items. To achieve this last goal, companies have worked with their sup-pliers, instructing them in statistical process control and, in some cases, showing how new equipment and procedures can be used to produce zero defect output. Suppliers become certified when they demonstrate that they can produce zero defect output. Their deliveries can then enter the production process with no incoming inspection performed. Any subsequent detection of defective items, of course, could lead to unhappy discussions between buyer and supplier. One materials manager, with tongue planted firmly in cheek, explained that his company understood : • how difficult it is to produce perfect parts and that we will accept a few rejects from our suppliers. We insist only that our suppliers first separate their bad parts from their good ones and ship them separately. • Furthermore, if a delivery is going to be late, our materials manager requests only that the supplier's vice president of marketing give our production workers a presentation on satisfying customers while they wait for the material to arrive.